As recently as January 2006 a new publication in the well-reputed journal Nature (Keppler et al., 2006) reported that green plants provide a hitherto unknown source for CH4. This was indeed a finding that drew much attention by news media as well as by CH4 research groups around the world. Production of CH4 in green plant parts per se had not been observed previously in spite of numerous works attempting to quantify the CH4-emissions strengths of soil-plant ecosystems.Our research questions were: Can we confirm an aerobic CH4 release? Is the source to CH4 release a small or large pool? Does CH4 release also occur at lower temperatures? Does the UV-component in light enhance the CH4 release?
Results/Conclusions
CH4-efflux by detached plant material was measured as increase in [CH4] in 60 ml glass vials, either through time or in comparison with empty control vials. 500 μL of the head space was sampled with a pressure-lock syringe and measured on a FID gas chromatograph. In our study we show that this phenomenon may occur even at low temperatures and that the rate of CH4 efflux from plant material is strongly dependent on UV-irradiation. Further, we show that the potential for CH4 efflux from plant material varies between species and that it is indirectly adjusted by endogenous plant and microbial enzymes.